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P.S.:COMPARABLE and equality.

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  • Arno Wagner
    P.S.: There are two questions here: 1. Do we get a same_type implicit assertion on the equality in COMPARABLE as a consequence of totality? Seems to me like
    Message 1 of 4 , Aug 16, 2002
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      P.S.: There are two questions here:

      1. Do we get a 'same_type' implicit assertion on
      the equality in COMPARABLE as a consequence
      of totality?

      Seems to me like that, unless I did overlook something.

      2. What about the postcondition 'symmetric' on
      'standard_is_equal' (and associates) in GENERAL?
      Does it need revision? Or does it need bug-fixes
      in the compiler(s)?

      Regards,
      Arno

      --
      Arno Wagner, Communication Systems Group, ETH Zuerich, wagner@...
      GnuPG: ID: 1E25338F FP: 0C30 5782 9D93 F785 E79C 0296 797F 6B50 1E25 338F
      ----
      For every complex problem there is an answer that is clear, simple,
      and wrong. -- H L Mencken
    • Emmanuel STAPF [ES]
      Hi, I should have asked the question when the discussion about COMPARABLE started, but could someone summarize what is wrong with the existing specification of
      Message 2 of 4 , Aug 16, 2002
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        Hi,

        I should have asked the question when the discussion about COMPARABLE
        started, but could someone summarize what is wrong with the existing
        specification of the class in ELKS 95. My believe is that we should try
        to fix bugs if any, to ensure that assertions are well defined (like we
        did in ARRAY and STRING) and then try to find solutions for mismatch
        between different Eiffel vendors.

        Manu

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      • Arno Wagner
        ... Right. From my point of view there is only one major issue in COMPARABLE: Is it right to use is_equal for equality. At the moment it looks to me like
        Message 3 of 4 , Aug 16, 2002
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          On Fri, Aug 16, 2002 at 04:06:07PM -0700, Emmanuel STAPF [ES] wrote:
          > Hi,
          >
          > I should have asked the question when the discussion about COMPARABLE
          > started, but could someone summarize what is wrong with the existing
          > specification of the class in ELKS 95. My believe is that we should try
          > to fix bugs if any, to ensure that assertions are well defined (like we
          > did in ARRAY and STRING) and then try to find solutions for mismatch
          > between different Eiffel vendors.
          >
          > Manu

          Right. From my point of view there is only one major issue
          in COMPARABLE: Is it right to use 'is_equal' for equality.
          At the moment it looks to me like there is not much choice
          anyway.

          In the process of thinking about this, I stumbled over the
          possible problem with the "equality" features in GENERAL,
          which I mainly posted to be sure I understood it, and if
          I do, to mark as something to be done when next visiting
          GENERAL.

          There are some minor things in the specifiation (invariants,
          preference of min/max of the first argument, postconditions),
          that do however not have any or any major impact on
          functionality. I do not see any code being broken by any
          of the discussed changes, as they all just relax the
          specification or re-formulate it.

          See Jim's and my last post for the equality question.
          See my initial post or Jim's last post for the minor things.

          Regards,
          Arno

          --
          Arno Wagner, Communication Systems Group, ETH Zuerich, wagner@...
          GnuPG: ID: 1E25338F FP: 0C30 5782 9D93 F785 E79C 0296 797F 6B50 1E25 338F
          ----
          For every complex problem there is an answer that is clear, simple,
          and wrong. -- H L Mencken
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